A prominent group of anti-euro German economists and business leaders has formed a political party to challenge Germany's support for euro-zone bailouts, a move that could test the ruling center-right coalition's hold on conservative votes in the fall general election.

With just six months until the election, the new party, which calls itself Alternative for Germany, is unlikely to gain enough traction to win seats in Parliament, analysts say. Yet even if the party comes in below the 5% threshold needed to win representation,...